01 - Bring beef tenderloin steaks to room temperature for 20-30 minutes. Pat thoroughly dry with paper towels to ensure proper searing.
02 - Generously season both sides of each steak with kosher salt and freshly ground black pepper, pressing the seasoning into the meat.
03 - Heat olive oil and 1 tablespoon butter in a large skillet over medium-high heat until shimmering and slightly smoking.
04 - Add steaks to the hot pan and sear for 3-4 minutes per side for medium-rare doneness. Adjust timing to reach preferred internal temperature.
05 - Transfer steaks to a plate and tent loosely with aluminum foil. Let rest for at least 5 minutes while preparing the sauce.
06 - Reduce heat to medium. Add drained green peppercorns to the same skillet and toast for 30 seconds until fragrant.
07 - Pour in white wine, scraping up browned bits from the bottom of the pan. Simmer until reduced by half, approximately 2-3 minutes.
08 - Stir in beef stock and continue simmering until slightly reduced, about 2 minutes.
09 - Lower heat and add heavy cream with Dijon mustard. Simmer gently, stirring frequently, until sauce thickens and coats the back of a spoon, 3-4 minutes.
10 - Remove from heat and stir in remaining 1 tablespoon butter. Taste and adjust seasoning with salt as needed.
11 - Return rested steaks to the pan to coat in sauce, or arrange on plates and spoon sauce generously over each steak.